How to Clear CREO 2.0 Parameter Names

I used parameter names (tools/parameters) to set up the model to be parametric with ANSYS Workbench. I am creating a new model and want to use the same parameter names as another model. I started a new session of CREO 2.0, created a new part, named the dimensions and then when I tried to create the parameter, I got a message that the Parameter name was already in session.

How do you clear parameter names? The old names do not show up in the Parameter List.